System and method for adjusting movement of an irrigation apparatus

ABSTRACT

A system and method for adjusting movement of an irrigation apparatus to help compensate for transient conditions occurring during operation of the apparatus to accomplish a substantially uniform fluid application rate, and including transient conditions such as a detected actual speed of movement of the span across the field is lesser or greater than expected or such as a detected actual flow rate of fluid to the irrigation system is lesser or greater than expected.

BACKGROUND Field

The present disclosure relates to irrigation movement systems and moreparticularly pertains to a new system and method for adjusting movementof an irrigation apparatus to help compensate for transient conditionsoccurring during operation of the system.

SUMMARY

In one aspect, the present disclosure relates to a method of controllingmovement of an irrigation system in a field based upon at least onetransient condition in the field. The irrigation system may include aspan movable over the field, with the span being supported by aplurality of towers and at least one of the towers having at least onewheel resting on the ground surface of the field and being rotatable toadvance the span across the field, and at least one of the towers has amotor assembly to rotate the wheel of the tower. The method may compriseproviding a remote control unit on the irrigation system, with theremote control unit including a location determination assemblyconfigured to determine a location of the remote control unit on thespan at a time. The method may further comprise receiving a selectedfluid application rate by the remote control unit, detecting an initiallocation of the remote control unit by the location determinationassembly, determining an expected distance of movement of the remotecontrol unit over at least one time interval at an initial movementspeed, and moving the span for a time interval in a manner correspondingto the selected fluid application rate. The method may also comprise, atan end of the time interval, detecting a first intermediate location ofthe remote control unit by the location determination assembly,determining an actual distance of movement during said time intervalbased upon the initial location and the first intermediate location,comparing the actual distance of movement to the expected distance ofmovement, determining if there is a deviation between the actualdistance of movement and the expected distance of movement, and if adeviation exists, then determining a magnitude of the deviation; and ifthere is a deviation, then calculating an adjusted movement speed for asubsequent time interval.

In another aspect, the disclosure relates to a method of controllingmovement of an irrigation system in a field based upon at least onetransient condition in the field. The irrigation system may include aspan movable over the field, the span being supported by a plurality oftowers, at least one of the towers having at least one wheel resting onthe ground surface of the field and being rotatable to advance the spanacross the field, and at least one of the towers having a motor assemblyto rotate the wheel of the tower. The method may comprise providing aremote control unit on the irrigation system, with the remote controlunit including a location determination assembly configured to determinea location of the remote control unit on the span at a time. The methodmay further comprise receiving a selected fluid application rate by theremote control unit, establishing a baseline rate of fluid flow from thepump, determining an initial movement speed based upon the baseline flowrate of the pump and the selected fluid application rate, and moving thespan for an initial time interval at the initial movement speed,detecting a first actual flow rate of the pump during the initial timeperiod. The method may also comprise comparing the first actual flowrate to the baseline rate, determining if there is a flow deviationbetween the first actual flow rate and the baseline rate, and if theflow deviation exists, then determining a magnitude of the flowdeviation. The method may also include calculating an adjusted movementspeed for a subsequent time interval, with the adjusted movement speedbeing calculated to achieve the selected application rate at the firstactual flow rate.

In still another aspect, the disclosure relates to a system forcontrolling movement of an irrigation system in a field based upon atleast one transient condition in the field. The irrigation system mayinclude a span movable over the field, the span being supported by aplurality of towers with at least one of the towers having at least onewheel resting on the ground surface of the field and being rotatable toadvance the span across the field, at least one of the towers having amotor assembly to rotate the wheel of the tower, and a control wire fortransmitting a control signal to the motor assembly. The system maycomprise a remote control unit positionable on the span of theirrigation system, and having an input for interfacing to an upstreamportion of the control wire and an output for connecting to a downstreamportion of the control wire in communication with the motor assembly.The remote control unit may include a location determination assemblyconfigured to determine a location of the remote control unit on thespan at a time, a processor, and data storage. The processor may beconfigured to execute a program of instructions to receive a selectedfluid application rate via the input of the remote control unit, detectan initial location of the remote control unit using location data fromthe location determination assembly, determine an expected distance ofmovement of the remote control unit over at least one time interval atan initial movement speed, and transmit a control signal via the outputof the remote control unit to the motor assembly to cause the span tomove for a time interval in a manner corresponding to the selected fluidapplication rate. The program of instruction may also be configured to,at an end of the time interval, detect a first intermediate location ofthe remote control unit using location data from the locationdetermination assembly, determine an actual distance of movement duringsaid time interval based upon the initial location and the firstintermediate location, compare the actual distance of movement to theexpected distance of movement, determine if there is a deviation betweenthe actual distance of movement and the expected distance of movement,and if a deviation exists, then determine a magnitude of the deviation.The program may also be configured to, if there is a deviation, thencalculate an adjusted movement speed for a subsequent time intervalcorresponding to the adjusted movement speed, and transmit the adjustedcontrol signal corresponding via the output of the remote unit to themotor assembly.

There has thus been outlined, rather broadly, some of the more importantelements of the disclosure in order that the detailed descriptionthereof that follows may be better understood, and in order that thepresent contribution to the art may be better appreciated. There areadditional elements of the disclosure that will be described hereinafterand which will form the subject matter of the claims appended hereto.

In this respect, before explaining at least one embodiment orimplementation in greater detail, it is to be understood that the scopeof the disclosure is not limited in its application to the details ofconstruction and to the arrangements of the components, and theparticulars of the steps, set forth in the following description orillustrated in the drawings. The disclosure is capable of otherembodiments and implementations and is thus capable of being practicedand carried out in various ways. Also, it is to be understood that thephraseology and terminology employed herein are for the purpose ofdescription and should not be regarded as limiting.

As such, those skilled in the art will appreciate that the conception,upon which this disclosure is based, may readily be utilized as a basisfor the designing of other structures, methods and systems for carryingout the several purposes of the present disclosure. It is important,therefore, that the claims be regarded as including such equivalentconstructions insofar as they do not depart from the spirit and scope ofthe present disclosure.

The advantages of the various embodiments of the present disclosure,along with the various features of novelty that characterize thedisclosure, are disclosed in the following descriptive matter andaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The disclosure will be better understood and when consideration is givento the drawings and the detailed description which follows. Suchdescription makes reference to the annexed drawings wherein:

FIG. 1 is a schematic perspective view of elements of an irrigationsystem according to the present disclosure.

FIG. 2A is a schematic block diagram of elements of one illustrativeembodiment of the system in which a remote control unit is employed.

FIG. 2B is a schematic block diagram of elements of another illustrativeembodiment of the system in which a remote control unit and a controlpanel unit are employed.

FIG. 3 is a schematic diagram of selected control elements of the systemaccording to an illustrative embodiment.

FIG. 4 is a schematic diagram of selected elements of the systemaccording to an illustrative embodiment, particularly showing the pathof fluid flow from the pump to the span.

FIG. 5A is a schematic diagram of a first portion of one method ofoperation, according to an illustrative implementation.

FIG. 5B is a schematic diagram of a second portion of the method ofoperation of FIG. 3A, according to an illustrative implementation.

FIG. 6A is a schematic diagram of a first portion of another method ofoperation, according to an illustrative implementation.

FIG. 6B is a schematic diagram of a second portion of the method ofoperation of FIG. 4A, according to an illustrative implementation.

FIG. 7 is a schematic diagram of operational aspects of the system andmethod, according to an illustrative implementation.

FIG. 8 is a schematic diagram of operational aspects of the system andmethod, according to an illustrative implementation.

DETAILED DESCRIPTION

With reference now to the drawings, and in particular to FIGS. 1 through8 thereof, a new system and method for adjusting movement of anirrigation apparatus embodying the principles and concepts of thedisclosed subject matter will be described.

Typical irrigation systems, movement of the irrigator structure isintended to proceed at a uniform rate that is not intended to vary inorder to provide a uniform fluid application rate across theagricultural field. Applicants have recognized that in the actual fieldenvironment, transient conditions may make this ideal uniform movementdifficult if not impossible, and that these transient conditions may bevirtually impossible to predict prior to startup of system operation.Such transient conditions may include, for example, variations in theactual movement progress of the irrigation structure across the fieldwhich decrease (or increase) the distance traveled across some portionsof the field. Thus, even though the structure is being driven at thesame speed throughout the field, conditions such as mud, obstructions,variations in terrain, and the like may deviate the actual movementdistance from the ideal movement distance. These variations in movementcan affect the amount of fluid that is actually applied to the field, asslower than expected movement applies more fluid to the field thanintended and faster than expected movement results in a less thanintended fluid application rate.

Another transient condition is the rate at which fluid, usually water,is supplied to the irrigation system. Typically water is supplied from apump drawing from a well or a body of water or even a water supplysystem, and the availability of water will fluctuate as water isdepleted from the ground aquifer or body of water (and then replenishedby rain) or as the water supply system experiences variations in waterdemands. As the water flow rate varies, so does the ability of theirrigation system to deliver water to the field. The speed at which theirrigation system moves across the field is typically based upon asingle uniform flow rate that may not be maintained throughout the day,much less a growing season. Consequently, these variations in flow fromthe fluid source can affect the amount of fluid that is actually appliedto the field, as lower than expected flow rates may apply less fluid tothe field than intended, and higher than expected flow rates result in afluid application rate that is greater than intended.

Applicants have further recognized the need for a system that is able todetect transient conditions that potentially affect the fluidapplication rate, and are also able to adjust the movement speed of thestructure of the irrigation system to attempt to minimize the effect ofthe condition upon the actual fluid application rate and bring theapplication rate back to the application rate selected by the user asmuch as possible.

In some aspects, the disclosure relates to a method of controllingmovement of an irrigation system in a field and adjusting the operationbased upon at least one transient condition occurring in the field, inorder to accomplish a substantially uniform fluid application rate ofthe fluid onto the surface of the field. In other aspects, thedisclosure relates to a system and apparatus that carries out, or atleast contributes to, the execution of elements of the method. Detectionof conditions may occur at various time intervals, and may typicallyoccur at regular and substantially uniform time intervals, althoughvarying time intervals may be utilized. The length of the time intervalsutilized may include any suitable time interval. In someimplementations, the time interval may be greater than one minute, andin some implementations the time interval may be less than approximately30 minutes. In some implementations, the time interval may be betweenapproximately 1 minute and approximately 30 minutes, and may be betweenapproximately 1 minute and approximately 15 minutes.

For the purposes of this disclosure, transient conditions are conditionsof a type that may arise during a cycle of operation the operation ofthe system in the field and that are relatively unpredictable as to theduration and the magnitude of deviation from an expected or base linestate for the particular condition. For example, the transient conditionmay include a detected actual distance of movement of structure of theirrigation system in the field that deviates from an expected movementdistance. As another example, the transient condition may include adetected actual flow rate of fluid to the irrigation system thatdeviates from a baseline flow rate. Other transient conditions mayinclude detectable conditions that may affect the actual fluidapplication rate, and the effect on the fluid application rate may beameliorated or lessened through the adjustment of the movement speed ofthe structure of the irrigation system. The system and method disclosedmay help to compensate for the effect of one or more transientconditions on the fluid application rate.

In one aspect, the disclosure relates to an irrigation system 10 thatincludes a span 12 which carries a fluid such as water from an inboardend 14 to an outboard end 16 to dispense fluid to locations along thespan onto distributed areas of the field surface. Although aspects ofthe disclosure may be implemented on irrigation systems of variousconfigurations and geometries, one of the most preferred applications ison a center pivot irrigation system configuration, and will be describedin that environment with the understanding that aspects may be easilyadapted to other irrigation system arrangements. The span 12 may extendoutwardly from a center of rotation located generally at the inboard end14, and thus may rotate about the center. Typically, the span 12includes a plurality of span segments 20 that are connected together ina substantially linear arrangement, but often with some flexibility inthe connection such that deviation from a completely linear arrangementis possible. The span segments 20 may be formed by pipe that carries thefluid along the span, and that are suitable connected in fluidcommunication at the junctures of the span segments. The plurality ofspan segments 20 may include an end span segment 22 with the outboardend 16 at the end of the end span segment.

The span 12 may be supported above the field surface by one or moretowers 24, and typically a plurality of towers are employed with a towerbeing located adjacent to each (although not necessarily every) juncturebetween span segments. An end tower 26 may be the tower positionedrelatively closest to the outboard end 14 of the span. At least one ofthe towers 24 has a wheel 28 resting on the ground surface of the fieldand which is rotatable by a motor assembly 30 to advance the span acrossthe field. Commonly, each tower will have a pair of the wheels 28, andeach tower will have a motor assembly. The motor assembly 30 maycomprise a motor 32 and a power control 34 for controlling the supply ofpower to the motor, and thereby the operation (or in operation) of themotor and the wheels connected to the motor. In some embodiment, thepower control 34 may include a relay.

The irrigation system 10 may also include a control wire 36 from a maincontrol apparatus 38 of the irrigation system to the power control 34.In many embodiments, the main control apparatus 38 may be set to aselected fluid application rate by a user, such as a farmer in thefield, and in some popular implementations the fluid application rate isset as a percentage of the maximum application rate achievable by theirrigation system. The maximum application rate is usually achieved atthe slowest movement speed for the span, and the conversely the minimumapplication rate is achieved at the fastest movement speed.Conventionally, the drivetrain (e.g., motor and wheels) of a span on thesystem is only able to turn at one speed, so to change the speed ofmovement of the span requires a series of “on” and “off” cycles for themotor assembly to turn the wheels, and in this sense (and for thepurposes of this description), the term “movement speed” relates to thetotal time that would be required for the span to make one revolution,and not the actual velocity of the span. Thus, the greater the amount oftime that the motor assembly is in an “on” cycle as compared to the timethat it is in an “off” cycle, the relatively faster the movement speedof the span. Conventionally, the on and off cycle times are controlledby the main control apparatus 38 (according to the set selectedapplication rate) via a control signal transmitted along the controlwire 36 by the control apparatus 38. The control signal generallycorresponds to the selected fluid application rate, and may berepresented on the control wire by a period that includes a sub-periodof power on and a sub-period of power off. For example, if a completecycle includes 60 seconds, the sub-period of power on may be 40 seconds,and the sub-period of power off may be 20 seconds, providing anapproximately 66% duty cycle. Increasing the number of seconds in the oncycle and decreasing the number of seconds in the off cycle willincrease the movement speed of the span. In many irrigation systeminstallations, the control signal is used to control the movement of theendmost tower (adjacent to the en span segment) and the remainder of thetowers move in a “follow the leader” manner that is conventional andwell known to those skilled in the art.

The irrigation system 10 may also include a fluid supply which is often(although not necessarily) a ground well, a body of water or awatercourse. A pump 40 is often used to move the fluid from the fluidsupply to the span, and a flow rate detector 42 may be associated withthe pump or a pipe leading to the span to detect the actual flow rate ofthe fluid to the span as the availability of water from these sourcesmay not be consistent. The flow rate detector 42 may generate a flowrate signal that corresponds to the actual flow rate being detected bythe detector at any given time.

Another aspect of the disclosure relates to a remote control unit 44suitable to be used with an irrigation system, such as a system 10 withelements disclosed herein (see FIGS. 2A and 2B). FIG. 2A shows oneimplementation in which a remote control unit may be employed withoutdirect interface with the main control apparatus 38 of the span, such asfor functions such as speed control and end spray gun control, butoptionally may be interfaced through a control panel interface tocontrol functions such as movement direction, and start/stop operations.FIG. 2B shows another implementation in which a remote control unit 44is utilized with a control panel unit 45 which may be interfaced withthe main control apparatus of the system. In the implementation shown inFIG. 2B, the remote control unit and control panel unit may communicatein any suitable manner, such as by wire or wirelessly, such as by radiofrequency signals using any suitable communication frequencies andprotocols, including but not limited to Wi-Fi, Wi-MAX, Bluetooth, andthe like. In embodiments employing both units 44, 45, many of thevarious functions described in this disclosure (even if described asbeing performed by one or the other of the units) may suitably beperformed by either of the units.

The remote control unit 44 is a device that may be controlled remotelythrough a communication channel that is most preferably wireless, butoptionally could be conducted through a wire. Further, communicationwith the remote control unit 44 may be bidirectional through atransceiver, although the ability to receive signals is most importantto suitable operation. The control unit is remote in the sense that itmay be controlled from a location that is remote from the device,typically miles if not hundreds of miles away, although the distance isnot critical. The control of the unit 44 may be exercised through acommunication network, such as a communication network utilizingcellular transmission and receiving devices and frequencies, althoughwireless communication networks utilizing other technologies andfrequencies may also be utilized. The elements that exercise control ofthe remote control unit 44 may utilize aspects of the technologydisclosed in U.S. Pat. No. 7,953,550 issued May 31, 2011, which ishereby incorporated by reference in its entirety.

The remote control unit 44 may be configured as a device that may becarried on the span and may be housed in a case that is capable ofresisting the elements and exposure encountered in an agriculturalfield. The remote control unit 44 may have an input 46 and an output 48,with the input 46 being connectable to the control wire 36 to receivethe control signal and the output being connectable to the power control34 of the motor assembly 30. The remote control unit may be configuredand programmed to receive the control signal on the control wire throughthe input 46, and determine the selected fluid application rate selectedby the user by, for example, sampling the signal over a full period anddetermining the relative length of the on period and the off period. Theremote control unit may generate and transmit through the output 48 amodified control signal to the motor assembly 30 to provide operation ofthe motor assembly that may be different from the operation that wouldbe effected if the control wire with the control signal were supplieddirectly to the motor assembly without the intervention of the remotecontrol unit. Under some conditions, the control signal at the output 48may not be modified from the signal at the input 46.

The remote control unit 44 may also include a location determinationassembly 50 that is configured to determine a location of the remotecontrol unit at a particular time, or at time intervals. The locationdetermination assembly 50 may provide the location in terms of a set oflocation coordinates, such as longitude and latitude. In some of themost preferred embodiments, the location determination assembly 50includes a Global Positioning Satellite (GPS) signal receiver forreceiving GPS satellite signals (as well as other positioning signals)that indicate the coordinates of the location of the unit 44, as well asthe tower or other portion of the span on which the unit 44 may bemounted or carried.

The remote control unit 44 may further include a communication meanssuitable for communicating over longer distances for the purpose ofcommunicating with entities at a greater distance. For example, theentity may be accessible through a wireless communication network andthe entity may reside on a data or computer communication network,although use of wired communication channels such as the Plain OldTelephone System (POTS) system may be used to less advantage. In one ofthe preferred implementations of the invention, a cellular telephonesystem is utilized as a wireless means of communication and a cellulartransceiver 52 is employed in the remote control unit 44 to providecommunication ability to a cellular antenna or tower 54 in the region ofthe center pivot irrigation system. The entity may thus be a web server56 that is able to communicate with the cellular telephone (or POTS)communication network as well as a data communication network 58 (e.g.,the Internet). Other means for communicating may be employed, but asaccess points to cellular networks (i.e., antenna towers) become moreubiquitous, even in rural areas, the cellular transceiver 52 is able toprovide wireless communication to the cellular network 58 (and thusprovide access to the POTS network) without having to run a hard wiredconnection to the field, which can be prohibitively expensive. It willbe recognized by those skilled in the art that the type or types ofnetworks may be varied without departing from the spirit of thedisclosure. The cellular transceiver 52 of the remote control unit isthus able to communicate with the web server 56 through the cellularnetwork 58 by a data transmission channel through the network.Optionally, the cellular transceiver may dial up the server throughvoice communication channel. The web server 56 is thereby able toreceive location and status information from the remote control unit 44,while the server is able to provide operational instructions andprograms of instructions to the remote control unit and other units. Theweb server 56 is in turn accessible by the user's communication device60 (which may comprise a computer, a personal digital assistant, asmartphone, or virtually any device with the ability to at least receiveand display information) through a data communication network (e.g.,Internet) or other communication network. The user is thus able tocommunicate instructions, or programs of instructions, to the remotecontrol unit 44. The remote control unit and/or the control panel unitmay also include a processor for providing information and communicationprocessing functions, as well as storage for storing, for example, dataand instructions for moving and operating various aspects of the system10.

The flow rate detector 42 may be provided with a suitable means ofcommunicating the flow rate signal to at least one of the units 44, 45and/or the web server. The communication may be carried using wired orwireless means such as radio frequency transmissions using any suitablecommunication frequencies and protocols, including but not limited toWi-Fi, Wi-MAX, Bluetooth, and the like. Optionally, the flow ratedetector may communicate with the web server in any suitable manner,such as cellular network communication.

Another aspect of the disclosure relates to the method of controllingmovement of an irrigation system, such as a system having some or all ofthe elements and attributes described above with respect to system 10,in a manner that compensates or adjusts for transient conditions such asthe actual movement progress of the span over the surface of the field.The method may include providing an irrigation system with one or moreelements described in this disclosure.

The method may include providing a control with some or all aspectsdescribed herein for the remote control unit 44, and may also includeproviding the span 12 with the remote control unit 44. The step ofproviding may involve positioning the remote unit 44 on the span, suchas at a position toward the outboard end 16 of the span and may be onthe end span segment 22. In some implementations, the unit 44 may bepositioned adjacent to the end tower which is highly beneficial toincrease the accuracy for determining location and also is convenientfor controlling the end tower. Providing the remote control unit 44 onthe span may further include interfacing the unit 44 with the controlsof the irrigation system, and may include severing the control wire 36to create an upstream portion 36A of the control wire in communicationwith the main control apparatus 38 and a downstream portion 36B incommunication with the power control 34 of the motor assembly 30. Theinterfacing step may also include connecting the upstream portion 36A ofthe control wire to the input 46 of the control unit 44, and connectingthe downstream portion 36B of the control wire to the output 48 of theunit 44.

The method may also comprise the step of receiving the selected fluidapplication rate by the remote control unit 44, which may includereceiving the control signal by the input 46 of the control unit 44through the upstream portion 36A of the control wire. In someimplementations, the receiving step may include monitoring and decodingthe control signal to determine, for example, a ratio of the time forthe sub-period of power on to the time for the sub-period of power off.This information regarding the user selected fluid application rate mayform the basis for setting the initial movement speed for the span,which would be the continuous movement speed throughout the rotation ofthe span if the conditions in the field were not subject to transientconditions that may call for changes in the movement speed as the spanis making a complete rotation cycle. In embodiments utilizing a controlpanel unit 45, the selected fluid application rate may be received bythe panel unit 45.

Another step of the method may be to calculate an expected distance ofmovement of the remote control unit 44 over at least one time intervalat the base or initial movement speed, and the distance of movement ofthe unit 44 will generally correspond to the distance moved by the endtower 26 if the unit is positioned adjacent to, or on, the end tower.The expected distance of movement by the unit 44 may be affected by, andthus may be based upon, the selected application rate (which providesthe initial movement speed), a time interval between locationdeterminations, and the distance of the remote control unit from thecenter of rotation of the span. The expected movement distance for eachtime interval will typically be substantially equal, and the step mayinclude calculating an expected location for the control unit 44 aftereach of the time intervals of a complete revolution of the span,although this is not necessary. The base movement speed may represent amovement speed for ideal conditions, such as level and dry groundconditions in which wheel slippage is not a significant factor in theactual movement distance achieved.

The method may also include detecting an initial location of the remotecontrol unit 44 by the location determination assembly 50 of the unit44, and may include determining the location coordinates of the unit 44via the GPS receiver. The initial location may be stored in memory forlater use in determining the distance moved by the control unit over oneor more time intervals.

A further aspect of the method may include moving the span 12 for thetime interval in a manner corresponding to the selected fluidapplication rate which typically the initial movement speed. Aspreviously stated, the span may not be moving throughout the entire timeinterval, as the movement of the span usually involves a sub-period ofmovement and a sub-period of non-movement when the span is stopped. Thestep may include providing power to the motor assembly for at least aportion of the time interval, such as the sub-period of power on. Thecontrol signal provided to the motor assembly may be modified, but insome situations or conditions, the control signal may not be modified,such as when the unmodified control signal would provide the suitablemovement speed.

Approximately at the end of the time interval, the method contemplatesdetecting a first intermediate location of the remote control unit 44via operation of the location determination assembly 50. Using the firstintermediate location information, the method may include determining anactual distance of movement during time interval based upon the distancebetween the initial location and the first intermediate location. Then,using the actual distance of movement, the method may also includecomparing the actual distance of movement to the expected distance ofmovement. It may be determined if there is a deviation of differencebetween the actual distance of movement and the expected distance ofmovement, and if a deviation in the distances exists, a magnitude of thedeviation.

If no deviation exists between the actual and expected distances ofmovement, then the method may include continuing to move the span at theinitial (or optionally the most recently-used) movement speed for thenext time interval so that the movement distance after that subsequentinterval may be checked against the expected movement distance over theinterval. If a deviation in movement distances is detected, then themethod may optionally contemplate determining if the magnitude of thedeviation exceeds a permitted level of deviation, which may be a degreeof deviation below which the difference is so minimal or inconsequentialthat it can be ignored. If the magnitude of the deviation does notexceed the permitted level of deviation, then the initial (or mostrecent) movement speed may be maintained through the subsequent timeinterval until the actual and expected distances are compared again.

In cases where the magnitude of the deviation is large enough that itneeds to be addressed, such as if it exceeds the permitted level ofdeviation, then the method may include determining if the deviation ofthe actual distance of movement is greater or lesser than the expecteddistance of movement. In other words, determining if the movement of thespan caused the control unit 44 to fall short of the expected location(e.g., undershoot), or exceed the expected location (e.g., overshoot).

As a further option, the method may include a step of determining if themagnitude of the deviation is in a range of correctable deviations, ordeviations that are of too great of a magnitude for it to be practicalor feasible to attempt to correct the deviation. The range ofcorrectable deviations may vary depending upon various factors, and thecapability to correct may depend, for example, upon the relative lengthof the time interval over which the deviation may be attempted to becorrected as longer time intervals provide a greater time period overwhich to make an adjustment of the movement speed. Optionally, there maynot be any deviation that is too large for the system to attempt tocorrect, although this approach may not be practical. If it isdetermined that the magnitude of the deviation is not in the range ofcorrectable deviations, then the system may provide a notice to theuser's computer or electronic device via the communication network ofthe inability to attempt to correct the deviation. In someimplementations, an adjusted movement speed may be set for thesubsequent time interval that is a predefined maximum speed if thedeviation is negative (e.g., the actual distance moved by the span isless than the expected distance) or that is a predefined minimum speedif the deviation is positive (e.g., the actual distance moved by thespan is greater than the expected distance).

In the case where the magnitude of the deviation is in the range ofcorrectable deviations, then a step of calculating an adjusted movementspeed for the subsequent time interval may be performed. The adjustedmovement speed may be calculated to cause the span 12 to move the remotecontrol unit 44 for a corrective distance such that an actual distanceof movement over the immediate past time interval and the subsequenttime interval is substantially equal to a combination of the expecteddistances of movement for the two time intervals.

When a corrective distance is determined, an adjusted control signal maybe generated, such as by the remote control unit, that corresponds tothe adjusted movement speed. The adjusted control signal may be providedor transmitted to the motor assembly through the downstream control wire36B to cause the motor assembly 30 to operate at a speed thatcorresponds to the adjusted movement speed. In some embodiments, theuser may be notified of the adjustment of the movement speed, such as bya transmission through the communication network to the user'scommunication device.

Steps of the process may be repeated for each time interval until systemoperation is ceased. In some implementations, once the actual movementdistance substantially corresponds to the expected movement distance ata time interval, the movement speed for the subsequent time interval maybe the initial movement speed, or in some implementations may be theadjusted movement speed of the most recent time interval.

An illustrative operational example is shown in FIG. 7, whichschematically illustrates a relationship between the expected movementdistances, actual movement distances, and movement speeds. As shown inthe upper line of FIG. 7, the expected movement distances are calculatedand expected to be substantially uniform from one time interval to thenext in order to achieve a complete movement (e.g., rotation) of thespan in a given overall time period to achieve the selected fluidapplication rate. The span is expected to move from position A toposition B in the first time interval, from position B to position C inthe second time interval, and so on. As shown in the second line of FIG.7, in which the actual distance of movement are illustrated, after thefirst time interval the actual movement distance is less than theexpected movement distance, and actual position B is short of theexpected position B. As illustrated in the third line of FIG. 7, themovement speed of the span is increased in the second time interval ascompared to the first time interval (e.g., from an initial movementspeed to a faster movement speed) to attempt to compensate for theshortfall in the actual movement distance during the first timeinterval. As shown in the first and second lines of FIG. 7, after thesecond time interval the deficit has been made up and the actualposition C substantially corresponds to the expected position C as theactual movement distance over the second time interval has exceeded theexpected movement distance to a sufficient degree to make up for theprior deficit. Since the expected and actual positions C correspond, themovement speed for the third time interval may be returned to theinitial movement speed.

Further illustrated in FIG. 7 is that during the third time interval,the actual movement distance exceeds the expected movement distance, sothat actual position D is further along the path of movement thanexpected position D. Consequently, the movement speed in the fourth timeinterval is decreased relative to the initial movement speed to a degreethat is calculated to make the actual position E at the end of thefourth time interval correspond to the expected position E. After thefourth time interval, the surplus travel distance after the third timeinterval has been compensated for, and the actual position Esubstantially corresponds to the expected position E. The movement speedof the span may be decreased to the initial movement speed for the fifthtime interval.

A further aspect of the disclosure relates to the method of controllingmovement of an irrigation system in a manner that compensates or adjustsfor a transient conditions such as the actual flow rate of fluid to thespan as compared to, for example, the expected or usual or baseline flowrate provided to the span. The method may include providing anirrigation system with one or more elements described in thisdisclosure, and may further include establishing a baseline rate offluid flow from the pump for use in comparing to the actual flow rateobserved at time intervals as the system operates. The establishment ofthe baseline rate may include detecting and recording a normal flow ratefrom the pump under typical conditions, or even calculating an averageflow rate from various times and various conditions.

The method may further include receiving the selected fluid applicationrate, such as by the remote control unit 44 or the control panel unit45, as indicated through the action of the user at the main controlapparatus or by other means. In some implementations, the remote controlunit may determine a base or initial movement speed of the span basedupon the baseline flow rate of the pump and the selected fluidapplication rate. The initial movement speed may form a normal or basemovement speed used when the actual flow rate is substantially equal tothe baseline flow rate. The span may be moved for the time interval in amanner that generally corresponds to the selected fluid applicationrate, which may include causing power to be provided to the motorassembly for at least a portion of the time interval through the controlsignal on the downstream portion of the control wire. The control signalmay be modified or may be unmodified as compared to the control signalsupplied to the remote control unit.

The method may further include detecting a first actual flow rate of thepump for the time interval, such as by receiving the flow rate signalfrom the flow rate detector 42. The flow rate measurement may be asingle instantaneous or momentary measurement of the flow rate at somepoint during the time interval, or may be a composite or average ofmultiple flow measurements over the relevant time interval. The remotecontrol unit may receive the actual flow rate measurement, and maycompare the first actual flow rate to the baseline rate and determine ifthere is a flow deviation as the first actual flow rate deviates fromthe baseline rate. If a flow deviation exists, then a magnitude of theflow deviation may be determined.

If it is determined that no significant flow deviation exists betweenthe first actual flow rate and the baseline rate, then the span may becaused to continue to move at the initial or base movement speed. If itis determined that there is a flow deviation between the actual andbaseline flow rates, then it may further be determined if the magnitudeof the flow deviation exceeds a permitted or acceptable level of flowdeviation. If the magnitude of the flow deviation is within thepermitted level of flow deviation, then the span may be continued to bemoved at the base movement speed.

If the magnitude of the flow deviation exceeds the permitted level offlow deviation, then a determination if the flow deviation of the flowrate is greater or lesser than the baseline flow rate may be made. Themethod may further include making a determination if the magnitude ofthe flow deviation is in a range of correctable flow deviations, or flowdeviations that may be compensated for through the alteration oradjustment of the movement speed of the span. If the magnitude of theflow deviation is determined to not be in the range of correctable flowdeviations, then a notice may be provided to the user that indicates theinability to sufficiently adjust the speed to adequately or effectivelycompensate for the flow deviation. In such an instance, an adjustedmovement speed may be set for the subsequent time interval that is apredefined maximum speed if the deviation is negative (e.g., the actualflow rate is less than the baseline flow rate) or that is a predefinedminimum speed if the deviation is positive (e.g., the actual flow rateis greater than the baseline flow rate).

If the magnitude of the flow deviation is in the range of correctabledeviations, then the method may include the step of calculating anadjusted movement speed for the subsequent time interval, with theadjusted movement speed being calculated to achieve the selectedapplication rate at the first actual flow rate. In some implementations,a first actual flow rate in which the flow deviation is below thebaseline rate results in an adjusted movement speed that is slower thanthe base movement speed, and a first actual flow rate in which thedeviation is above the baseline rate results in an adjusted movementspeed that is faster than the base movement speed.

When a corrective adjusted movement speed is determined, an adjustedcontrol signal may be generated that corresponds to the adjustedmovement speed. The adjusted control signal may be provided ortransmitted to the motor assembly through the downstream control wire36B to cause the motor assembly 30 to operate at a speed thatcorresponds to the adjusted movement speed. In some embodiments, theuser may be notified of the adjustment of the movement speed, such as bya transmission through the communication network to the user'scommunication device.

Steps of the process may be repeated for each time interval until systemoperation is ceased. In some implementations, when the actual flow ratesubstantially corresponds to the baseline flow rate at a time interval,the movement speed for the subsequent time interval may be the basemovement speed, or in some implementations may be the adjusted movementspeed of the most recent time interval.

An illustrative operational example is shown in FIG. 8, whichschematically illustrates a relationship between the baseline flow rate,actual flow rates, and movement speeds. As shown in the upper line ofFIG. 8, the baseline flow rate is calculated and expected to besubstantially uniform from one time interval to the next in order toachieve a substantially uniform fluid application rate to achieve theselected fluid application rate. In the illustration, during the firsttime interval, the actual flow rate is detected to be less than thebaseline flow rate (the baseline flow rate is indicated by a brokenline), and during the second (subsequent) time interval the movementspeed is adjusted and decreased to a degree that is calculated to applyfluid on the field at the selected application rate at the reduced flowrate detected. During the second time interval, it is detected that theactual flow rate approximately corresponds to the baseline flow rate,and so the movement speed is returned to the base movement speed overthe third interval. During the third time interval, it is determinedthat the actual flow rate is greater than the baseline flow rate, soduring the fourth (subsequent) time interval, the movement speed isadjusted to be faster than the base movement speed. As the actual flowrate is approximately equal to the baseline flow rate in the fourth timeinterval, then the movement speed is adjusted back to the base movementspeed during the fifth time interval.

It should be recognized that the system and method of the disclosure maydetect and compensate for two or more transient conditions during thesame period of operation, and may make multiple adjustments to themovement speed for a time interval, some of which may decrease or evencancel out each other. In some implementations, compensation based uponone of the conditions may be given priority over compensation foranother condition. For example, in a system which detects variations inboth actual movement and flow rate, the calculated compensation fordecreased flow rate may take priority over any compensation for anactual movement distance that falls short of the expected distance. Inother implementations, amelioration of all conditions may be given equalpriority.

It should be appreciated that in the foregoing description and appendedclaims, that the terms “substantially” and “approximately,” when used tomodify another term, mean “for the most part” or “being largely but notwholly or completely that which is specified” by the modified term.

It should also be appreciated from the foregoing description that,except when mutually exclusive, the features of the various embodimentsdescribed herein may be combined with features of other embodiments asdesired while remaining within the intended scope of the disclosure.

Further, those skilled in the art will appreciate that the steps shownin the drawing figures may be altered in a variety of ways. For example,the order of the steps may be rearranged, substeps may be performed inparallel, shown steps may be omitted, or other steps may be included,etc.

With respect to the above description then, it is to be realized thatthe optimum dimensional relationships for the parts of the disclosedembodiments and implementations, to include variations in size,materials, shape, form, function and manner of operation, assembly anduse, are deemed readily apparent and obvious to one skilled in the artin light of the foregoing disclosure, and all equivalent relationshipsto those illustrated in the drawings and described in the specificationare intended to be encompassed by the present disclosure.

Therefore, the foregoing is considered as illustrative only of theprinciples of the disclosure. Further, since numerous modifications andchanges will readily occur to those skilled in the art, it is notdesired to limit the disclosed subject matter to the exact constructionand operation shown and described, and accordingly, all suitablemodifications and equivalents may be resorted to that fall within thescope of the claims.

We claim:
 1. A method of controlling movement of an irrigation system ina field based upon at least one transient condition in the field, theirrigation system including a span movable over the field, the spanbeing supported by a plurality of towers, at least one of the towershaving at least one wheel resting on the ground surface of the field andbeing rotatable to advance the span across the field, at least one ofthe towers having a motor assembly to rotate the wheel of the tower, themethod comprising: providing a remote control unit on the irrigationsystem, the remote control unit including a location determinationassembly configured to determine a location of the remote control uniton the span at a time; receiving a selected fluid application rate bythe remote control unit; detecting an initial location of the remotecontrol unit by the location determination assembly; determining anexpected distance of movement of the remote control unit over at leastone time interval at an initial movement speed, moving the span for atime interval in a manner corresponding to the selected fluidapplication rate; at an end of the time interval, detecting a firstintermediate location of the remote control unit by the locationdetermination assembly; determining an actual distance of movementduring said time interval based upon the initial location and the firstintermediate location; comparing the actual distance of movement to theexpected distance of movement; determining if there is a deviationbetween the actual distance of movement and the expected distance ofmovement, and if a deviation exists, then determining a magnitude of thedeviation; and if there is a deviation, then calculating an adjustedmovement speed for a subsequent time interval.
 2. The method of claim 1wherein, if no deviation exists between the actual and expecteddistances of movement, then continuing to move the span at the initialmovement speed.
 3. The method of claim 1 wherein the adjusted movementspeed is calculated to cause the remote control unit to be moved by thespan a corrective distance such that an actual distance of movement overan immediate past time interval and the subsequent time interval issubstantially equal to a combination of the expected distances ofmovement for the two time intervals.
 4. The method of claim 1additionally comprising generating an adjusted control signal by theremote control unit corresponding to the adjusted movement speed andproviding the adjusted control signal to the motor assembly to cause themotor assembly to operate at a speed corresponding to the adjustedmovement speed.
 5. The method of claim 1 additionally comprisingnotifying the user of the adjustment of the movement speed.
 6. Themethod of claim 1 wherein providing the remote control unit on theirrigation system includes positioning the remote unit on the span at alocation spaced from a center of rotation of the span.
 7. The method ofclaim 1 wherein providing the remote control unit on the irrigationsystem includes interfacing the remote control unit with a control wireof the irrigation system.
 8. The method of claim 7 wherein interfacingthe remote control unit includes severing the control wire to create anupstream portion of the control wire in communication with a maincontrol apparatus of the irrigation system and a downstream portion incommunication with the motor assembly, and connecting the upstreamportion of the control wire to an input of the remote control unit andconnecting the downstream portion of the control wire to an output ofthe remote control unit.
 9. The method of claim 8 additionallycomprising outputting a modified control signal from the remote controlunit on the output to the motor assembly, the modified control signalcorresponding to the adjusted movement speed.
 10. The method of claim 1wherein determining the expected distance of movement includescalculating the expected distance of movement using the selectedapplication rate, the time interval, and a distance of the remotecontrol unit from a center of rotation of the span.
 11. The method ofclaim 1 wherein determining the expected distance of movement includescalculating the expected distance of movement for each time interval ofa complete revolution of the span.
 12. The method of claim 1 whereinmoving the span includes providing power to the motor assembly for atleast a portion of the time interval.
 13. A method of controllingmovement of an irrigation system in a field based upon at least onetransient condition in the field, the irrigation system including a spanmovable over the field, the span being supported by a plurality oftowers, at least one of the towers having at least one wheel resting onthe ground surface of the field and being rotatable to advance the spanacross the field, at least one of the towers having a motor assembly torotate the wheel of the tower, the method comprising: providing a remotecontrol unit on the irrigation system, the remote control unit includinga location determination assembly configured to determine a location ofthe remote control unit on the span at a time; receiving a selectedfluid application rate by the remote control unit; establishing abaseline rate of fluid flow from the pump; determining an initialmovement speed based upon the baseline flow rate of the pump and theselected fluid application rate; moving the span for an initial timeinterval at the initial movement speed; detecting a first actual flowrate of the pump during the initial time period; comparing the firstactual flow rate to the baseline rate; determining if there is a flowdeviation between the first actual flow rate and the baseline rate; ifthe flow deviation exists, then determining a magnitude of the flowdeviation; and calculating an adjusted movement speed for a subsequenttime interval, the adjusted movement speed being calculated to achievethe selected application rate at the first actual flow rate.
 14. Themethod of claim 13 additionally comprising moving the span at anadjusted movement speed that is slower than the initial movement speedwhen the first actual flow rate is less than the baseline rate.
 15. Themethod of claim 13 additionally comprising moving the span at anadjusted movement speed that is faster than the initial movement speedwhen the first actual flow rate is greater than the baseline rate. 16.The method of claim 13 additionally comprising, if no flow deviationexists between the first actual flow rate and the baseline rate,continuing to move the span at the initial movement speed.
 17. Themethod of claim 13 additionally comprising, if the magnitude of the flowdeviation is not in a range of correctable flow deviations, then settingthe adjusted movement speed to a minimum movement speed or a maximummovement speed over the subsequent time interval.
 18. A system forcontrolling movement of an irrigation system in a field based upon atleast one transient condition in the field, the irrigation systemincluding a span movable over the field, the span being supported by aplurality of towers, at least one of the towers having at least onewheel resting on the ground surface of the field and being rotatable toadvance the span across the field, at least one of the towers having amotor assembly to rotate the wheel of the tower, and a control wire fortransmitting a control signal to the motor assembly, the systemcomprising: a remote control unit positionable on the span of theirrigation system, the remote control unit having an input forinterfacing to an upstream portion of the control wire and an output forconnecting to a downstream portion of the control wire in communicationwith the motor assembly, the remote control unit including: a locationdetermination assembly configured to determine a location of the remotecontrol unit on the span at a time; a processor; data storage; whereinthe processor is configured to execute a program of instructions to:receive a selected fluid application rate via the input of the remotecontrol unit; detect an initial location of the remote control unitusing location data from the location determination assembly; determinean expected distance of movement of the remote control unit over atleast one time interval at an initial movement speed; transmit a controlsignal via the output of the remote control unit to the motor assemblyto cause the span to move for a time interval in a manner correspondingto the selected fluid application rate; at an end of the time interval,detect a first intermediate location of the remote control unit usinglocation data from the location determination assembly; determine anactual distance of movement during said time interval based upon theinitial location and the first intermediate location; compare the actualdistance of movement to the expected distance of movement; determine ifthere is a deviation between the actual distance of movement and theexpected distance of movement, and if a deviation exists, then determinea magnitude of the deviation; if there is a deviation, then calculate anadjusted movement speed for a subsequent time interval corresponding tothe adjusted movement speed, and transmit the adjusted control signalcorresponding via the output of the remote unit to the motor assembly.